My favorite .22LR pistol is the out-of-production S&W 422 / 622. They are not pure target guns, but they are a lot of fun to shoot and are very well made. They are very light weight and so they are perfect for younger shooters. After that I like the S&W M&P 22. Same deal; fun, accurate and reliable. I have two of them and they have nothing but awesome.
The most accurate .22LR pistol I have is a Ruger 22/45 MKIII but my wife and kids always go for the 422 / 622 or the M&P 22. They feel the Ruger is too heavy and they don't like the grip.
You could always just buy a Tac Sol .22LR conversion upper for your Glock too. They are a little buggy but a lot of people have and love them.